Causes and incidenceAutoimmune thyroiditis is due to antibodies to thyroid antigens in the blood. It may cause inflammation and lymphocytic infiltration (Hashimoto’s thyroiditis). Glandular atrophy (myxedema) and Graves’ disease are linked to autoimmune thyroiditis.

Miscellaneous thyroiditis results from bacterial invasion of the gland in acute suppurative thyroiditis; tuberculosis, syphilis, actinomycosis, or other infectious agents in the chronic infective form; and sarcoidosis and amyloidosis in chronic noninfective thyroiditis. Postpartum thyroiditis (silent thyroiditis) is another autoimmune disorder associated with transient thyroiditis in females within 1 year after delivery.

Thyroiditis is most prevalent among people ages 30 to 50 and is more common in females than in males. Incidence is highest in the Appalachian region of the United States.

Signs and symptomsAutoimmune thyroiditis is usually asymptomatic and commonly occurs in females, with peak incidence in middle age. It’s the most prevalent cause of spontaneous hypothyroidism.

In subacute granulomatous thyroiditis, moderate thyroid enlargement may follow an upper respiratory tract infection or a sore throat. The thyroid may be painful and tender, and dysphagia may occur.

In Riedel’s thyroiditis, the gland enlarges slowly as it’s replaced by hard, fibrous tissues. This fibrosis may compress the trachea or the esophagus. The thyroid feels firm.

Clinical effects of miscellaneous thyroiditis are characteristic of pyogenic infection: fever, pain, tenderness, and reddened skin over the gland.

DiagnosisPrecise diagnosis depends on the type of thyroiditis:

❑ Autoimmune: high titers of thyroglobulin and microsomal antibodies present in serum

TreatmentAppropriate treatment varies with the type of thyroiditis. Drug therapy includes levothyroxine for accompanying hypothyroidism, analgesics and anti-inflammatory drugs for mild subacute granulomatous thyroiditis, propranolol for transient hyperthyroidism, and steroids for severe episodes of acute inflammation. Suppurative thyroiditis requires antibiotic therapy. A partial thyroidectomy may be necessary to relieve tracheal or esophageal compression in Riedel’s thyroiditis.

Special considerationsBefore treatment, obtain a patient history to identify underlying diseases that may cause thyroiditis, such as tuberculosis or a recent viral infection.

❑ Check the patient’s vital signs, and examine her neck for unusual swelling, enlargement, or redness. Provide a liquid diet if she has difficulty swallowing, especially when due to fibrosis. If the neck is swollen, measure and record the circumference daily to monitor progressive enlargement.

❑ Administer antibiotics as ordered, and report and record elevations in temperature.

❑ Instruct the patient to watch for and report signs of hypothyroidism (lethargy, restlessness, sensitivity to cold, forgetfulness, and dry skin), especially if she has Hashimoto’s thyroiditis, which often causes hypothyroidism.